Chemistry

Organic Chemistry Fundamentals

237 Questions

Organic chemistry fundamentals cover the structure, properties, and reactions of carbon containing compounds. The questions explore functional groups, isomerism, homologous series, and basic reaction mechanisms. This forms the basis of general chemistry across multiple examination formats.

Functional groupsIsomerism typesHomologous seriesCycloalkanesOrganic monomers

Organic Chemistry Fundamentals Questions

Multiple choice

The minimum number of carbon atoms that must be present in an alkene is

  1. 1

  2. 2

  3. 3

  4. 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alkenes are the carbon compounds with at least one double covalent bond between their carbon atoms. Double covalent bonds are formed when each atom contributes two electrons. Carbon cannot form a double covalent bond with hydrogen as hydrogen has only one valence electron. Therefore, alkene containing one carbon (i.e. methane) does not exist. The minimum number of carbon atoms that must be present in an alkene is two. Ethene (C2H4) is the simplest alkene containing two carbon atoms. 

Multiple choice

Which set of molecules is expect to be of amphoteric nature?

  1. Al(OH)3, Al2O3, GeO

  2. H2SiO3, SiO2, CO2

  3. Mg(OH)2, PbO, PbO2

  4. PbO, PbO2, GeO

  5. SiO2, GeO, PbO2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Al(OH)3 is amphoteric hydroxide, Al2O3 is amphoteric oxide and GeO is amphoteric oxide. Hence, Al(OH)3, Al2O3 and GeO are all expected to be of amphoteric nature.

Multiple choice

Which pair of xenon compounds has trigonal pyramidal and T-shaped geometries respectively?

  1. XeF4, XeOF2

  2. XeF6, XeOF2

  3. XeO3, XeOF2

  4. XeO3, XeF4

  5. XeOF2, XeO2F2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

XeO3 has sp3 hybridization with one lone pair of electrons and has trigonal pyramidal geometry. XeOF2 has sp3d hybridization with two lone pairs of electrons and has T-shaped geometry. Hence, the pair of compounds of Xe, i.e. XeO3 and XeOF2 have trigonal pyramidal and T-shaped geometries respectively.

Multiple choice

An octane number of 100 is assigned to ...................

  1. 2,2,4-trimethylpentane

  2. 2-methylbutane

  3. 2,2-dimethylbutane

  4. 2,2-dimethylpentane

  5. 2-methylhexane
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The burning efficiency of gasoline is rated by an octane number scale. An octane number of 100 is assigned to 2,2,4-trimethylpentane (also known as isooctane), which is an excellent fuel.

Multiple choice

2AlCl3 represents

  1. two atoms of Aluminium Chloride

  2. two molecules of Aluminium Chloride

  3. three atoms of Chlorine

  4. two atoms of Aluminium
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

2AlCl3 represents two molecules of aluminium chloride.

Multiple choice chemistry chemical reactions of organic compounds alkanoic acids nomenclature of carboxyl group nomenclature of carboxylic acids

The correct structural formula of butanoic acid is

  1. $H-\overset{H}{\overset{|}{\underset{H}{\underset{|}{C}}}}-\overset{H}{\overset{|}{C}}=\overset{H}{\overset{|}{C}}-\overset{O}{\overset{||}{C}}-OH$
  2. $H-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\underset{H}{\underset{|}{\overset{O}{\overset{||}{C}}}}-OH$
  3. $H-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-OH$
  4. $H-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\overset{O}{\overset{||}{C}}-OH$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Butanoic acid is a carboxylic acid with the structural formula CH3CH2CH2-COOH. where $-COOH$ is the functional group.

$H-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\underset{H}{\underset{|}{\overset{H}{\overset{|}{C}}}}-\overset{O}{\overset{||}{C}}-OH$

So, the correct representation of butanoic acid is $D$
Multiple choice chemistry hydrocarbons introduction to alkenes - ethyne acetylene alkynes

$H-C\equiv C-H+NaNH _{2}\longrightarrow A\overset{2 \ mole \ CH _3I}{\longrightarrow}B$


Then B is :

  1. 1-Butyne

  2. 2-Butyne

  3. 2-Pentyne

  4. Propyne
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Reaction of process:
$CH\equiv CH+2NaNH _2\rightarrow NaC\equiv CNa\xrightarrow {2 mole CH _3I} CH _3CH\equiv CHCH _3$


Option B is correct.

Multiple choice law of reciprocal proportion laws of chemical combination basic concepts of chemistry some basic concepts of chemistry chemistry

Which one of the following sets of compound correctly illustrates the law of reciprocal proportions?

  1. $P _2O _3, PH _3, H _2O$
  2. $P _2O _5, PH _3, H _2O$
  3. $N _2O _5, NH _3, H _2O$
  4. $N _2O, NH _3, H _2O$
  5. $NO _2, NH _3, H _2O$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In $PH _3$, the ratio by weight of $P:H=31:3$

For $H _2O, O:H= 16:2=8:1$
Keeping the weight of $H(=1)$ fixed, $P:O=\cfrac {31}{3}:\cfrac {8}{1}=31:24\longrightarrow (1)$
In $P _2O _5, P:O$ is $(2 \times 31):(5 \times 16)$
$=62:80$ or $31:40 \longrightarrow (2)$
Keeping the weight of $P(=31)$ fixed in equation (1) & (2), the ratio of oxygen is $24:40$ or $3:5$ which is a simple ratio.